Reading test strip with reaction area, color calibration area, and temperature calibration area

ABSTRACT

A method is provided for a computing device with an imaging device to read a specimen test strip. The method includes capturing an image of the specimen test strip, wherein the image includes a reaction area, a color calibration area, and a temperature calibration area on the specimen test strip, determining a color of the reaction area based on one or more colors of the color calibration area, and determining a value of a characteristic of an analyte by correlating the color of the reaction area to the value and then adjusting the value based on the color of the temperature calibration area, or adjusting the color of the reaction area based on the color of the temperature calibration area and then correlating the color of the reaction area to the value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Division of U.S. patent application Ser. No.13/798,175, filed Mar. 13, 2013, which claims the benefit of U.S.Provisional Application No. 61/749,811, filed Jan. 7, 2013.

This application is related to U.S. patent application Ser. No.XX/XXX,XXX, Attorney Docket No. 151-0001-US-CON1, which is concurrentlyfiled on May 14, 2015.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference. For example,this application incorporates by reference in their entirety U.S.Provisional Application No. 61/749,811, filed Jan. 7, 2013, and U.S.patent application Ser. No. 13/798,175, filed Mar. 13, 2013, and U.S.patent application Ser. No. XX/XXX,XXX (Attorney Docket No.151-0001-US-CON1), filed May 14, 2015.

FIELD

The present disclosure generally relates to photometric analysis of oneor more analytes applied to a test strip.

BACKGROUND

FIG. 1 shows a prior art specimen test strip 100 with a reaction area102. Reaction area 102 contains reagents that react with an analyte in aspecimen sample, such as glucose in a blood sample. When the specimensample reaches reaction area 102, reaction area 102 changes coloraccording to a characteristic of the analyte, such as the glucose levelin blood. The user visually compares the color of reaction area 102against a chart 104 to correlate the color of reaction area 102 to thecharacteristic of the analyte. Alternatively the user inserts specimentest strip 100 into a meter, which optically determines thecharacteristic of the analyte.

SUMMARY

According to aspects of the present disclosure, a specimen test strip todetect a characteristic of an analyte in a specimen sample is providedwith a reaction area configured to receive the specimen sample, and acolor calibration area configured to determine a color of the reactionarea after receiving the specimen sample. In some embodiments, aplurality of reaction areas are provided, each configured to detect adifferent range of values of the characteristic of the analyte.

According to other aspects of the present disclosure, methods for acomputing device with an imaging device to read a specimen test strip todetect a characteristic of an analyte in a specimen sample are provided.In some embodiments, the method comprises capturing one or more imagesof the specimen test strip, wherein each image includes a reaction areaand a color calibration area on the specimen test strip. In theseembodiments, the method further comprises determining a color of thereaction area based on the color calibration area from the one or moreimages, and correlating the color of the reaction area to a value of thecharacteristic of the analyte.

In some embodiments, a method is provided which comprises capturing atleast two images of the specimen test strip, wherein each image includesa reaction area. The method further comprises determining a colorintensity change of the reaction area from the images, and determining atime difference between when the images were captured. The method alsocomprises correlating the color intensity change and the time differenceto a value of the characteristic of the analyte.

In some embodiments, a method is provided which comprises capturing afirst image of the specimen test strip. The image includes reactionareas, each configured to detect a different range of values of acharacteristic of an analyte. The method further comprises selecting oneof the reactions areas and correlating the selected reaction area to avalue of the characteristic of the analyte.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several embodiments in accordance with thedisclosure and are therefore not to be considered limiting of its scope,the disclosure will be described with additional specificity and detailthrough use of the accompanying drawings.

In the drawings:

FIG. 1 shows a prior art specimen test strip;

FIG. 2 shows a specimen test strip with a reaction area, a colorcalibration area, and a temperature calibration area in one or moreexamples of the present disclosure;

FIG. 3 shows a specimen test strip with a reaction area, a colorcalibration area, and a temperature calibration area in one or moreexamples of the present disclosure;

FIG. 4 shows an arrangement of a reaction area and a color calibrationarea in one or more examples of the present disclosure;

FIG. 5 shows an arrangement of a reaction area and a color calibrationarea in one or more examples of the present disclosure;

FIG. 6 shows part of a specimen test strip with a timer capillary in oneor more examples of the present disclosure;

FIG. 7 shows a specimen test strip with a reaction area and a timer areain one or more embodiments of the present disclosure;

FIG. 8 is a flowchart of a method for a computing device executing adiagnostic application to calibrate and read a specimen test strip inone or more examples of the present disclosure;

FIG. 9 is a chart illustrating curves plotting the change in a colorparameter over time for values of an analyte characteristic in one ormore examples of the present disclosure;

FIG. 10 is a flowchart of a method for a computing device executing adiagnostic application to use differential calculation to rapidly read aspecimen test strip in one or more examples of the present disclosure;

FIG. 11 is a flowchart of a method for a computing device executing adiagnostic application to track a user's diet along with an analytecharacteristic in one or more examples of the present disclosure;

FIG. 12 graphically illustrates an association of meals, times, andanalyte characteristic values over the course of a day in one or moreexamples of the present disclosure;

FIG. 13A shows a specimen test strip that includes a set of reactionareas to detect different ranges of values of an analyte characteristicin a specimen sample in one or more examples of the present disclosure;

FIGS. 13B, 13C, and 13D show the specimen test strip of FIG. 13A afterreceiving specimen samples having different values of an analytecharacteristic in one or more examples of the present disclosure;

FIG. 14 shows a specimen test strip that includes a set of reactionareas to detect different ranges of values of an analyte characteristicin a specimen sample in one or more examples of the present disclosure;

FIG. 15 shows a specimen test strip that includes a set of reactionareas to detect different ranges of values of an analyte characteristicin a specimen sample in one or more examples of the present disclosure;

FIG. 16 shows a specimen test strip that includes a set of reactionareas to detect different ranges of values of an analyte characteristicin a specimen sample in one or more examples of the present disclosure;

FIG. 17 is a flowchart of a method for a computing device executing adiagnostic application to read a specimen test strip with multiplereaction areas to detect different ranges of values of an analytecharacteristic in one or more examples of the present disclosure;

FIG. 18 shows a specimen test strip under different exposures to enhancethe details of certain reaction areas in one or more examples of thepresent disclosure;

FIG. 19 shows a specimen test strip under different flash strengths toenhance the details of certain reaction areas in one or more examples ofthe present disclosure;

FIG. 20 shows a specimen test strip that includes multiple reactionareas to detect values of characteristics of different analytes in oneor more examples of the present disclosure;

FIG. 21 is a cross-sectional view of a specimen test strip in one ormore examples of the present disclosure;

FIG. 22 is a chart illustrating curves plotting the change in a firstcolor over time for values of a characteristic of a first analyte in oneor more examples of the present disclosure; and

FIG. 23 is a chart illustrating curves plotting the change in a secondcolor over time for values of a characteristic of a second analyte inone or more examples of the present disclosure.

DETAILED DESCRIPTION

FIG. 2 shows an exemplary embodiment of a specimen test strip 200 in oneor more examples of the present disclosure. Specimen test strip 200includes a reaction area 202 to receive a specimen sample. Reaction area202 includes reagents to chemically react with the analyte in thespecimen sample and produce one or more color parameters that areproportional to the value of a characteristic of the analyte in thespecimen sample. In some embodiments, the one or more color parametersincludes the color or both the color and the color intensity of reactionarea 202. In one example, the color is the hue of reaction area 202 andthe color intensity is the lightness of reaction area 202. The hue andthe lightness are color components in the hue, saturation, and lightness(HSL) color space, which are determined from the red, green, and blue(RGB) values of pixels captured by a camera. For convenience, color andcolor intensity may be collectively referred to as color. The reagentsmay be analyte specific and may include one or more enzymes, one or moreantibodies, and/or one or more dyes. For example, reagents for testingglucose in blood may include glucose oxidase, heteropoly acid, andtetradecyl ammonium nitrate.

In one example, specimen test strip 200 includes a color calibrationarea 204 that is part of specimen test strip 200. In one example, colorcalibration area 204 is used to determine the color of reaction area 202under different lighting conditions. In such an example, colorcalibration area 204 may be a color chart having an arrangement of knowncolor samples. In another example, color calibration area 204 is used tocorrect the detected color of reaction area 202 to remove the effects ofthe light condition. In such an example, color calibration area 204 maybe a gray card of known reflectance (e.g., 18%) that serves as a whitebalance reference for color correction. Gray card 204 may also serve asan exposure reference when a computing device 210 captures an image 212of specimen test strip 200. In one example, color chart or gray card 204is printed on specimen test strip 200.

In one example, color calibration area 204 is a dummy reaction areahaving one or more known colors. In use, dummy reaction area 204 remainsthe same color or colors because it is devoid of one or more enzymes,one or more antibodies, or one or more dyes. In another example, dummyreaction area 204 remains the same color or colors because it does notreceive any specimen sample.

In one example, specimen test strip 200 includes a temperaturecalibration area 206 that is part of specimen test strip 200 along withreaction area 202 and color calibration area 204. Temperaturecalibration area 206 changes color according to its temperature and itis used to correct the color of reaction area 202 as the chemicalreaction between the reagents and the analyte may be affected by thetemperature of specimen test strip 200. In one example, temperaturecalibration area 206 includes an organic material such as athermochromic dye (e.g., leuco dyes such as spirolactones, fluorans,spiropyrans, or fulgides), an inorganic material such as titaniumdioxide, zinc oxide, or indium oxide, or a thermochromic liquid crystal.In another example, temperature calibration area 206 is a chip, amechanical device, or an electromechanical device that indicates atemperature. Instead of or in addition to using temperature calibrationarea 206, computing device 210 may use a built-in temperature sensor toapproximate or determine the temperature of reaction area 202.

Using an imaging device 208 on computing device 210, a user captures animage 212 of reaction area 202 and at least one of color calibrationarea 204 and temperature calibration area 206. Imaging device 208 may bea camera, a scanner, or another similar device, and computing device 210may be a smart phone, a tablet computer, a laptop computer, a desktopcomputer, or another similar device. Computing device 210 runs adiagnostic application that analyzes image 212 to determine the analytecharacteristic from the color of reaction zone 202.

In one example, the diagnostic application determines the color ofreaction area 202 using color calibration area 204 in image 212. Whencolor calibration area 204 is a color chart, the diagnostic applicationmatches the color of the entire or part of reaction area 202 to one ofthe known color samples of color calibration area 204 to determine thecolor of reaction area 202. Alternatively the diagnostic application maymanipulate image 212 until color chart 204 matches its known colors andthen reads all or part of the color of reaction area 202. When colorcalibration area 204 is a gray card, the diagnostic applicationmanipulates image 212 until gray card 204 in image 212 has the properwhite balance and then reads the color of reaction area 202.

In another example, the diagnostic application determines the color ofreaction area 202 using color calibration area 204 in image 212 andcorrects the color using temperature calibration area 206 in image 212.The diagnostic application determines the temperature of specimen teststrip 200 from temperature calibration area 206 or a built-intemperature sensor in computing device 210, and then corrects the colorof reaction area 202 for the temperature using a known relationshipbetween temperature and color for reaction area 202. This relationshipmay be determined experimentally, mathematically, or both. Thediagnostic application may perform the color correction usingtemperature calibration area 206 before or after any of the othercorrections described in the present disclosure.

In one example, the diagnostic application calibrates the illuminationof image 212 before using color calibration area 204 and temperaturecalibration area 206. The diagnostic application estimates anillumination profile of reaction area 202 to determine if theillumination is uniform. The diagnostic application determines theillumination profile from RGB values of at least two locations that spanreaction area 202 or color calibration area 204 (e.g., opposing cornerpixels 506 and 508 in FIG. 5). When the illumination profile between thetwo locations is greater than the noise level by a threshold amount(e.g., the illumination profile is twice the noise level), theillumination on reaction area 202 is not uniform and the diagnosticapplication corrects the illumination of image 212. In one example, thediagnostic application uses the following formula to correct theillumination of image 212:

RGB _(new) =i*(R(x,y), G(x,y), B(x,y))/(R _(est)(x,y), G _(est)(x,y), B_(est)(x,y))

where R(x,y), G(x,y), B(x,y) are the original RGB values of a pixel,R_(est)(x,y), G_(est)(x,y), B_(est)(x,y) are the estimated RGB values ofthe illumination profile at the same pixel, and i is the maximum RGBvalues for the color of the reaction area. For example, colorcalibration area 204 may include a white ring around reaction area 102.Assume in image 212 the RGB values of corner 506 are (200,200,200) andthat of corner 508 are (100,100,100). Further assume that theillumination profile is linear. Based on these assumptions, a whitepoint at a central pixel 510 of reaction area 502 in FIG. 5 would haveRGB values of (150,150,150). When the color at pixel 510 is not white,say it instead has RGB values of (125,75,75), the new RGB values for thecentral point are i*(125,75,75)/(150,150,150), where i is (255,255,255).

After the one or more calibrations described in the present disclosure,the diagnostic application samples pixels from reaction area 202 (e.g.,50 to 100 pixels) and determines their values for the one or more colorparameters (e.g., the color or the color and the color intensity). Thediagnostic application averages the values for the one or more colorparameters and correlates the one or more averaged color parameters tothe value of the analyte characteristic (e.g., the concentration levelof glucose in blood).

In one example, reaction area 202, color calibration area 204, andtemperature calibration area 206 are rectangular, and areas 204 and 206are located adjacent to the top and bottom sides of area 202,respectively. Reaction area 202, color calibration area 204, andtemperature calibration area 206 may take on other shapes andarrangements.

FIG. 3 shows a specimen test strip 300 with a different arrangement fora reaction area 302, a color calibration area 304, and a temperaturecalibration area 306 in one or more examples of the present disclosure.Color temperature area 306 is split into parts 306A and 306B, andreaction area 302 is sandwiched on the left and right sides by parts306A and 306B, respectively. Color calibration area 304 is adjacent tothe bottom side of the combination of reaction area 302 and temperaturecalibration area 306.

FIG. 4 shows an arrangement 400 of a reaction area 402 and a colorcalibration area 404 in one or more examples of the present disclosure.Color calibration area 404 surrounds reaction area 402. In one example,reaction area 402 has a circular shape and color calibration area 404has a ring shape.

FIG. 5 shows an arrangement 500 of a reaction area 502 and a colorcalibration area 504 in one or more examples of the present disclosure.Like arrangement 400 (FIG. 4), color calibration area 504 surroundsreaction area 502. However, reaction area 502 has a rectangular shapeand color calibration area 504 has a rectangular ring shape.

FIG. 6 shows part of a specimen test strip 600 with a timer capillary602 in one or more examples of the present disclosure. Specimen teststrip 600 represents a specimen test strip with any of the reactionarea, color calibration, and temperature calibration arrangementsdescribed in the present disclosure. Specimen test strip 600 includes acapillary entrance 604, a reaction capillary 606, and a reaction area608. Reaction capillary 606 connects capillary entrance 604 to reactionarea 608. Timer capillary 602 is connected to capillary entrance 604.Timer capillary 602 has a smaller cross-section than reaction capillary606. When a specimen sample is received at capillary entrance 604,reaction capillary 606 transports a majority of the specimen sample toreaction area 608 to detect the characteristic of the analyte. A smallportion of the specimen sample travels along timer capillary 602, whichis marked off with time durations so the progress of the specimen samplein timer capillary 602 is used as a timer to indicate when specimen teststrip 600 should be read.

FIG. 7 shows a specimen test strip 700 with a reaction area 702 and atimer area 704 in one or more embodiments of the present disclosure.Specimen test strip 700 represents a specimen test strip with any of thereaction area, color calibration, and temperature calibrationarrangements described in the present disclosure. Timer area 704 isanother reaction area to receive the specimen sample. For example, likespecimen test strip 600, specimen test strip 700 may include a reactioncapillary that connects a capillary entrance and reaction area 702, anda timer capillary that connects the capillary entrance to timer area704. Whereas reaction area 702 has reagents that produce a nonlinearreaction to the specimen sample, timer area 704 has reagents thatproduce a substantially linear reaction to the specimen sample so thecolor change of timer area 704 is used as a timer to indicate whenspecimen test strip 700 should be read. In one example, timer area 704is hermetically sealed and includes cobalt chloride (CoCl₂) that changesfrom blue to pink in response to the water molecules in the specimensample. Specimen test strip 700 may also include a color calibrationarea 706 and a temperature calibration area 708.

In one example, timer area 704 changes color in response to light oncespecimen test strip 700 is removed from an opaque sealed package. Timerarea 704 changes color linearly in response to light to indicate anamount of time that specimen test strip 700 has been removed from itspackage, which may approximate a reaction time of reaction area 702 witha specimen sample to indicate when specimen test strip 700 should beread. Timer area 704 may be covered by a clear protective membrane. Inone example, timer area 704 includes photochromic dyes such asazobenzens, salicylidene anilines, fulgides, spiropyrans, orspirooxazines.

In one example, timer area 704 changes color due to humidity oncespecimen test strip 700 is removed from a hermetically sealed package.Timer area 704 changes color linearly in response to humidity toindicate an amount of time since specimen test strip 700 has beenremoved from its package, which may approximate a reaction time ofreaction area 702 with a specimen sample to indicate when specimen teststrip 700 should be read. Timer area 704 may be covered by a perforatedclear protective membrane that controls the exposure to humidity. In oneexample, timer area 704 includes CoCl₂ that changes from blue to pink.

Instead of using timer area 704, computing device 210 may use a built-intimer to approximate the reaction time of reaction area 702 with thespecimen sample.

FIG. 8 is a flowchart of a method 800 for a computing device (e.g.,computing device 210 in FIG. 2) executing a diagnostic application toread a specimen test strip (e.g., specimen test strip 200 in FIG. 2) inone or more examples of the present disclosure. In any method describedin the present disclosure, although the blocks are illustrated in asequential order, these blocks may also be performed in parallel, and/orin a different order than those described herein. Also, the variousblocks may be combined into fewer blocks, divided into additionalblocks, and/or eliminated based upon the desired implementation. Method800 may begin in block 802.

In block 802, computing device 210 captures one or more images 212 ofspecimen test strip 200. Multiple images 212 may captured so that asteady image without any blurring may be selected from images 212.Images 212 may be images taken in a rapid succession (e.g., in acontinuous or rapid-fire mode) or frames from a video. In one example,each image 212 includes reaction area 202 and color calibration area204. In another example, each image 212 also includes temperaturecalibration area 206. In yet another example, each image 212 furtherincludes timer area 602 or 704.

When color calibration area 204 is a gray card, computing device 210 mayuse color calibration area 204 as an exposure reference for capturingimages 212. Alternatively computing device 210 may use an object (e.g.,grass or human skin) near specimen test strip that has about 18%reflectance as an exposure reference. Computing device 210 mayautomatically recognize the exposure reference or a user may directimaging device 208 at the exposure reference to set the proper exposure.

In one example, computing device 210 captures images 212 at anappropriate time after the specimen sample is placed on specimen teststrip 200. As previously described, timer area 602 or 704 may indicatewhen image 212 should be captured. Computing device 210 may monitortimer 602 or 704 and automatically capture image 212 or a user maydirect imaging device 208 to capture image 212 from visually inspectingtimer 602 or 704. Block 802 may be followed by optional block 803.

In optional block 803, computing device 210 selects a steady image 212without any blurring. The diagnostic application may determine if animage 212 is steady by using a built-in accelerometer in computingdevice 210 to determining if computing device 210 was steady when itcaptured image 212. The diagnostic application may also use the built-inaccelerometer to provide a warning when the user is not holdingcomputing device 210 steady when an image 212 is about to be captured.Optional block 803 may be followed by block 804.

In block 804, computing device 210 calibrates the illumination ofreaction area 202 in image 212. As previously described, computingdevice 210 estimates the illumination profile of reaction area 202 inimage 212 and then corrects the illumination of reaction area 202 inimage 212 when the illumination is not uniform. Block 804 may befollowed by block 806.

In block 806, computing device 210 determines the color of reaction area202 in image 212. As previously described, computing device 210 maydetermine the color of reaction area 202 based on color calibration area204 in image 212 when area 204 is a color chart. Otherwise computingdevice 210 simply reads the color of reaction area 202 from image 212.Block 806 may be followed by block 807.

In block 807, computing device 210 corrects the color of reaction area202 based on one or more calibration areas. In one example, computingdevice 210 corrects the color of reaction area 202 for white balancebased on color calibration area 204 in image 212 when area 204 is a graycard. In one example, computing device 210 corrects the color ofreaction area 202 for temperature based on temperature calibration area206 in image 212. Note the order of blocks 806 and 807 may be reversed.Block 807 may be followed by block 808.

In block 808, computing device 210 correlates the color or both thecolor and the color intensity of sample pixels from reaction area 202 inimage 212 to an analyte characteristic value (e.g., a glucose level).

The rate of the change in a color parameter in reaction area 202 maydepend on the analyte characteristic value. For each analytecharacteristic value, the rate of the change in the color parameter maybe plotted as a curve over time. FIG. 9 is a chart 900 illustratingthree curves 902, 904, and 906 plotting the change in a color parameter(e.g., color intensity) over time for three analyte characteristicvalues (e.g., three glucose levels). Each curve has a different slope ina time window (e.g., time window 908) that is unique to thecorresponding analyte characteristic value. Thus the difference betweenat least two values of the color parameter and the difference betweenwhen the two values are captured may be used to identify thecorresponding analyte characteristic value. The time window is locatedearlier, such as at 2 and 3 seconds after the specimen sample is placedon specimen test strip 200, than the time one should wait to read aconventional specimen test strip, such as 10 seconds or more.

FIG. 10 is a flowchart of a method 1000 for a computing device (e.g.,computing device 210 in FIG. 2) executing a diagnostic application touse differential calculation to rapidly read a specimen test strip(e.g., specimen test strip 200 in FIG. 2) in one or more examples of thepresent disclosure. Method 1000 may begin in block 902.

In block 1002, computing device 210 captures at least two images 212 ofspecimen test strip 200 in time window 908. Images 212 may be imagestaken in a rapid succession (e.g., in a continuous or rapid-fire mode)or frames from a video. For example, a first image 212 is captured at afirst time and a second image 212 is captured at a second time. The timedifference between the first and the second time is calculated as a timewindow (e.g., time window 908 shown in FIG. 9). Each image 212 includesreaction area 202 on specimen test strip 200. In one example, each image212 also includes color calibration area 204 on specimen test strip 200.In another example, each image further includes one or more additionalcalibration areas on specimen test strip 200, such as temperaturecalibration area 206. In one example, computing device 210 selectsimages 212 captured at time window 908 based on timer area 602 or 704.Block 1002 may be followed by a block 1004.

In block 1004, computing device 210 determines the color of reactionarea 202 in each image 212 using any of the methods described in thepresent disclosure, including illumination correction, color correction,and temperature correction. Block 1004 may be followed by block 1006.

In block 1006, computing device 210 determines a change in colorintensity of reaction area 202 from images 212. Block 1006 may befollowed by block 1008.

In block 1008, computing device 210 correlates the change in colorintensity to an analyte characteristic value. Computing device 210 mayuse chart 900, or the mathematical representation of chart 900, todetermine the analyte characteristic value. Specifically, computingdevice 210 moves time window 908 along curves 902, 904, and 906. Whenthe intensity change of a curve in the time window matches the intensitychange of reaction area 202, then reaction area 202 has the analytecharacteristic value of that curve.

FIG. 11 is a flowchart of a method 1100 for a computing device (e.g.,computing device 210 in FIG. 2) executing a diagnostic application totrack a user's diet along with an analyte characteristic in one or moreexamples of the present disclosure. Method 1100 may begin in block 1102.

In block 1102, computing device 210 captures an image of a meal. Block1102 may be followed by block 1104.

In block 1104, computing device 210 records a time of the meal. Block1104 may be followed by block 1106.

In block 1106, computing device 210 associates the meal and the time toan analyte characteristic value determined about the same time andrecords this association. The analyte characteristic value may bedetermined using any of the methods described in the present disclosure.Blocks 1102, 1104, and 1106 may be repeated to track a user's diet overtime. Block 1106 may be followed by block 1108.

In block 1108, computing device 210 displays the recorded association.Computing device 210 may also transmit the recorded association over acomputer network to another computing device, such as a doctor'scomputer, for treatment purposes. FIG. 12 graphically illustrates theassociation of meals, times, and analyte characteristic values over thecourse of a day in one or more examples of the present disclosure.

FIG. 13A shows a specimen test strip 1300 in one or more examples of thepresent disclosure. Specimen test strip 1300 includes a set of reactionareas 1302A, 1302B, 1302C, and 1302D (collectively as “reaction areas1302” or individually as a generic “reaction area 1302”). Each reactionarea 1302 is to detect a different range of values of an analytecharacteristic in the specimen sample. In one example for detectingglucose level, reaction area 1302A detects 0 to 100 milligrams perdeciliter (mg/dL), reaction area 1302B detects 0 to 200 mg/dL, reactionarea 1302C detects 0 to 400 mg/dL, and reaction area 1302D detects 0 to800 mg/dL. To detect different ranges of values of the analytecharacteristic, reaction areas 1302 have different concentrations of oneor more of the reagents. Alternatively reaction areas 1302 havedifferent reagents.

Specimen test strip 1300 may include a capillary entrance and acapillary running through contacting reaction areas 1302 to deliver aspecimen sample. Alternatively specimen test strip 1300 may include aspread zone that is overlapping and contacting reaction areas 1302 todistribute the sample to reaction areas 1302. The user may also manuallyspread the sample across reaction areas 1302 in an example without anystructure to deliver the sample to reaction areas 1302. Specimen teststrip 1300 may further include a color calibration area 1304 and atemperature calibration area 1306.

FIG. 13A shows specimen test strip 1300 in a pre-test condition. FIG.13B shows specimen test strip 1300 receiving a 150 mg/dL glucosespecimen sample in one or more examples of the present disclosure. Asthe concentration of glucose is higher than the range of reaction area1302A, it has an oversaturated color so it is not used to determine theglucose level. However, reaction areas 1302B, 1302C, and 1302D may beused. The color of reaction area 1302B has a nice saturation so it mayprovide a better reading than reaction areas 1302C and 1302D.

FIG. 13C shows specimen test strip 1300 receiving a 300 mg/dL glucosespecimen sample in one or more examples of the present disclosure. Asthe concentration of glucose is higher than the ranges of reaction areas1302A and 1302B, they have oversaturated colors so they are not used todetermine the glucose level. However, reaction areas 1302C and 1302D maybe used. The color of reaction area 1302C has a nice saturation so itmay provide a better reading than reaction area 1302D.

FIG. 13D shows specimen test strip 1300 receiving a 600 mg/dL glucosespecimen sample in one or more examples of the present disclosure. Asthe concentration of glucose is higher than the ranges of reaction areas1302A, 1302B, and 1302C, they have oversaturated colors so they are notused to determine the glucose level. The color of reaction area 1302Dhas a nice saturation so it is used to determine the glucose level.

In one example, reaction areas 1302 are rectangular and arranged in asingle column to have an overall rectangular parameter. Reaction areas1302 may take on other shapes and arrangements.

FIG. 14 shows a specimen test strip 1400 with a different arrangementfor reaction areas 1402A, 1402B, 1402C, and 1402D (collectively“reaction areas 1402”) in one or more examples of the presentdisclosure. In specimen test strip 1400, reaction areas 1402 are squareand arranged to have a square outer parameter. Like specimen test strip1300, specimen test strip 1400 may include structures to deliver asample to reaction areas 1402 or the user may manually spread the sampleacross reaction areas 1402.

FIG. 15 shows a specimen test strip 1500 with a different arrangementfor reaction areas 1502A, 1502B, 1502C, and 1502D (collectively“reaction areas 1502”) in one or more examples of the presentdisclosure. In specimen test strip 1500, reaction subareas 1502 aretriangular and arranged to have a square outer parameter. Like specimentest strip 1300, specimen test strip 1500 may include structures todeliver a sample to reaction areas 1502 or the user may manually spreadthe sample across reaction areas 1502.

FIG. 16 shows a specimen test strip 1600 with a different arrangementfor reaction areas 1602A, 1602B, 1602C, and 1602D (collectively“reaction areas 1602”) in one or more examples of the presentdisclosure. In specimen test strip 1600, a capillary entrance 1604 isconnected by capillaries 1606 to reaction areas 1602. Reaction areas1602 are equally spaced around capillary entrance 1604 at the samedistance from capillary entrance 1604.

FIG. 17 is a flowchart of a method 1700 for a computing device (e.g.,computing device 210 in FIG. 2) executing a diagnostic application toread a specimen test strip (e.g., specimen test strip 1300 in FIG. 13)with multiple reaction areas to detect different ranges of values of ananalyte characteristic in one or more examples of the presentdisclosure. Method 1700 may begin in block 1702.

In block 1702, computing device 210 captures an image of specimen teststrip 1300. The image including reaction areas 1302. As previouslydescribed, each reaction area 1302 is to detect a different range ofvalues of an analyte characteristic. Computing device 210 may determinethe color of each reaction area 1302 using any of the methods describedin the present disclosure. Block 1702 may be followed by block 1704.

In block 1704, computing device 210 selects a reaction area 1302 of theproper saturation. Computing device 210 examines reaction areas 1302from the one with the smallest range to the one with the largest range.When the average RGB values of a reaction area 1302 are close to itsnoise level (e.g., ˜10), which indicates that the analyte concentrationhas exceed its detection limit, computing device 210 proceeds to examinethe next reaction area 1302. This process continues until computingdevice 210 selects a reaction area 1302 where the average RGB values aregreater than its noise level. Block 1704 may be followed by block 1706.

In block 1706, computing device 210 correlates the color or the colorand the color intensity of the selected reaction area 1302 to an analytecharacteristic value.

Method 1700 may be extended by taking multiple images of specimen teststrip 1300 at multiple exposures in one or more examples of the presentdisclosure. FIG. 18 shows images 1802, 1804, and 1806 of specimen teststrip 1300 at 1/60, 1/30, and 1/15 seconds, respectively, in one or moreexamples of the present disclosure. On one extreme, image 1802 isunder-exposed to enhance the details of one or more reaction areas fordetecting higher concentrations (e.g., reaction area 1302D), and therebyincreasing the sensitivity of these reaction areas. On the otherextreme, image 1806 is over-exposed to enhance the details of one ormore reaction areas for detecting lower concentrations (e.g., reactionarea 1302B), and thereby increasing the sensitivity of these reactionareas. With an exposure in between the extremes, image 1804 enhance thedetails of one or more reaction areas for detecting mid concentrations(e.g., reaction area 1302C), and thereby increasing the sensitivity ofthese reaction areas.

Computing device 210 may select one of images 1802, 1804, and 1806 basedon the average RGB values of all of the reaction areas 1302 in eachimage. When the average RGB values of all of the reaction areas 1302 inan image is too low (e.g., <30) or too high (e.g., >240), whichindicates the exposure time of this image to be improper, computingdevice 210 selects another image.

Instead of adjusting the exposure, method 1700 may be extended by takingmultiple images of specimen test strip 1300 at multiple illuminationstrengths (e.g., flash or light strengths) in one or more examples ofthe present disclosure. FIG. 19 shows images 1902, 1904, and 1906 ofspecimen test strip 1300 at low, mid, and high flash strengths,respectively, in one or more examples of the present disclosure. On oneextreme, image 1902 is under a low illumination strength to enhance thedetails of one or more reaction areas for detecting lower concentrations(e.g., reaction area 1302A), and thereby increasing the sensitivity ofthese reaction areas. On the other extreme, image 1906 is under a highillumination strength to enhance the details of one or more reactionareas for detecting higher concentrations (e.g., reaction area 1302D),and thereby increasing the sensitivity of these reaction areas. With amid illumination strength, image 1904 enhance the details of one or morereaction areas for detecting mid concentrations (e.g., reaction area1302C), and thereby increasing the sensitivity of these reaction areas.

In this mode, computing device 210 may test the illumination source(e.g., flash) prior to capturing images 1902, 1904, and 1906 to ensureit is working properly. For example, computing device 210 turns on theflash at least once and uses the detected intensity change to determinewhether or not the flash is working.

Computing device 210 may select one of images 1902, 1904, and 1906 basedon the average RGB values of the entire or part of reaction areas 1302in each image. When the average RGB values of reaction areas 1302 in animage is either too low (e.g., <30) or too high (e.g., >240), whichindicates the lighting intensity of this image to be improper, computingdevice 210 selects another image.

FIG. 20 shows a specimen test strip 2000 in one or more examples of thepresent disclosure. Specimen test strip 2000 includes multiple reactionareas to detect values of characteristics of different analytes. In oneexample, specimen test strip 2000 includes a reaction area 2002 fordetecting a characteristic of a first analyte in a specimen sample, areaction area or reaction areas 2004 (e.g., two reaction areas 2004) fordetecting a characteristic of a second analyte in the specimen sample,and a reaction area or reaction areas 2006 (e.g., three reaction areas2006) to detect a characteristic of a third analyte in the specimensample. Like reaction areas 1302 described in FIG. 13A, multiplereaction areas 2004 each detect a different range of values of thecharacteristic of the second analyte, and multiple reaction areas 2006each detect a different range of values of the characteristic of thirdanalyte.

In one example, one analyte in the specimen sample is known to affectthe detection of another analyte. For example, reaction area 2006detects glucose in a blood sample and reaction area 2004 detects thelevel of hematocrit (HCT) in the blood sample. HCT level may be detecteddirectly or indirectly (i.e., by determining the level of anothersubstance in the blood sample). The diagnostic application determinesthe HCT level and then corrects the glucose level using a knownrelationship between the HCT and the glucose levels. This relationshipmay be determined experimentally, mathematically, or both. Thediagnostic application may perform the HCT correction before or afterany of the other corrections described in the present disclosure.

Computing device 210 may also determine the HCT level in other ways froma specimen test strip. FIG. 21 is a cross-sectional view of a specimentest strip 2100 in one or more examples of the present disclosure. Inspecimen test strip 2100, a hole is provided in a path of the bloodsample, a light is shone through the blood sample, and the resultinglight color is correlated to the HCT level. In one example, specimentest strip 2100 includes a capillary entrance 2102, a capillary 2104connected to capillary entrance 2102, and a reaction area 2106 connectedto capillary 2104. A hole 2108 is defined through capillary 2104. A topopening 2110 of hole 2108 is covered by a transparent film 2112 and abottom opening 2114 is covered by a transparent film 2116. Computingdevice 210 shines a light through hole 2108 and captures the color ofthe light exiting hole 2108, which depends on the percentage of redblood cells in the blood and is therefore correlated to the HCT level.In another example, film 2116 that is more reflective than film 2112.Part of the light is reflected or scattered back through top opening2110 and captured by computing device 210 to determine the HCT level.

In another example, a rectangular strip of a material that filters redblood cells and absorbs serum is provided on a specimen test strip. TheHCT level is then correlated to amount of serum absorbed, which isdetermined from the distance the blood sample travels up the strip.

Instead of using a timer area separate from a reaction area (e.g., timerarea 602 or 704), method 800 may be extended by using a second colorcomponent of a reaction area to detect time and a first color componentof the reaction area to detect an analyte characteristic in one or moreexamples of the present disclosure.

FIG. 22 is a chart 2200 illustrating curves plotting the change in afirst color component (e.g., red) of the reaction area over time forvalues of an analyte characteristic (e.g., glucose level in blood) inone or more examples of the present disclosure. As can be seen, thecurves of the first color components quickly settle to constant valuesand therefore they may be used to indicate the respective values of theanalyte characteristic.

FIG. 23 is a chart 2300 illustrating curves plotting the change in asecond color component (e.g., a blue component) of the reaction areaover time for values of the analyte characteristic in one or moreexamples of the present disclosure. As can be seen, the curves of thesecond color component changes with time and therefore it may be used asa timer to indicate when to read the first color component and determinethe value of the analyte characteristic (i.e., after the first colorcomponent settles). In one example, in block 802 of method 800,computing device 210 may capture multiple images 212, determine when thesecond color component indicates an appropriate time to read the firstcolor component, and read the first color component at that time todetermine a value of the analyte characteristic.

The test strips, systems and methods disclosed herein may be used totest for the presence and/or concentration of certain analytes, such asbut not limited to glucose, cholesterol, uric acid, troponin I, ketone,protein, nitrite and leukocyte. Various fluids may be tested, such asbut not limited to blood, interstitial fluid, urine, saliva, and otherbodily fluids.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

1. A method for a computing device with an imaging device to read aspecimen test strip to detect a characteristic of an analyte in aspecimen sample, comprising: capturing an image of the specimen teststrip, wherein: the image includes a reaction area, a color calibrationarea, and a temperature calibration area on the specimen test strip; thereaction area has a color based on the characteristic of the analyte;the color calibration area having one or more colors; and thetemperature calibration area has a color based on its temperature;determining the color of the reaction area based on the one or morecolors of the color calibration area; and determining a value of thecharacteristic of the analyte, comprising: correlating the color of thereaction area to the value of the characteristic of the analyte and thenadjusting the value of the characteristic of the analyte based on thecolor of the temperature calibration area; or adjusting the color of thereaction area based on the color of the temperature calibration area andthen correlating the color of the reaction area to the value of thecharacteristic of the analyte.
 2. The method of claim 1, wherein:determining the color of the reaction area comprises determining a colorintensity in addition to determining the color of the reaction areabased on the one or more colors of the color calibration area; andcorrelating the color of the reaction area comprises correlating thecolor intensity in addition to correlating the color of the reactionarea to a value of the characteristic of the analyte.
 3. The method ofclaim 2, further comprising selecting a steady image from multipleimages as the image for determining the color or the color and the colorintensity of the reaction area.
 4. The method of claim 1, wherein theimage comprises a frame of a video.
 5. The method of claim 1, furthercomprising: determining if an illumination of the image is uniform fromat least two locations on the color calibration area; and when theillumination of the image is not uniform, correcting the illumination'seffect on the image.
 6. The method of claim 5, wherein correcting theillumination's effect on the image comprises: determining anillumination profile from the at least two locations on the colorcalibration area; estimating RGB values of the illumination profile at apixel in the reaction area; and determining corrected RGB values of thepixel as follows:RGB _(new) =i*(R(x,y), G(x,y), B(x,y))/(Rest(x,y), Gest(x,y), Best(x,y))where R(x,y), G(x,y), B(x,y) are the original RGB values of the pixel,Rest(x,y), Gest(x,y), Best(x,y) are the estimated RGB values of theillumination profile at the pixel, and i is the maximum RGB values of acolor in the reaction area.
 7. (canceled)
 8. The method of claim 2,wherein the image further includes an other reaction area on thespecimen test strip, and the method further comprises correcting thecolor or the color and the color intensity of the reaction area based onthe other calibration area.
 9. The method of claim 8, wherein thereaction area detects a glucose level and the other reaction areadetects a hematocrit level.
 10. The method of claim 1, furthercomprising: directing a light through a top opening of a hole in a pathof the specimen sample in the specimen test strip; determining a colorof the light exiting from a bottom opening of the hole or reflected outfrom the top opening; correlating the color of the light to an othervalue of an other analyte characteristic; and correcting the color ofthe reaction area based on the other value of the other analytecharacteristic.
 11. The method of claim 10, wherein the analytecharacteristic is a glucose level and the other analyte characteristicis a hematocrit level.
 12. The method of claim 1, wherein the imagefurther includes a timer on the specimen test strip, and the methodfurther comprises determining when to capture the image based on thetimer.
 13. The method of claim 12, wherein the timer comprises a timercapillary.
 14. The method of claim 12, wherein the timer comprises atimer area that receives the specimen sample and changes color linearlyin response to the specimen sample.
 15. The method of claim 12, whereinthe timer comprises a timer area that changes color in response to lightor humidity when the specimen test strip is removed from a package. 16.The method of claim 2, wherein: determining the color or the color andthe color intensity of the reaction area based on the one or more colorsof the color calibration area comprises determining a first colorcomponent of the reaction area after determining a second colorcomponent of the reaction area indicates an appropriate time to read thefirst color component of the reaction area; and correlating the color orthe color and the color intensity of the reaction area to the value ofthe characteristic of the analyte comprises correlating the first colorcomponent to the value of the characteristic of the analyte.
 17. Themethod of claim 1, further comprising: capturing an image of a meal at atime; associating the image of the meal, the time, and the value of thecharacteristic of the analyte; and displaying or transmitting anassociation of the image of the meal, the time, and the value of thecharacteristic of the analyte.